Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India.
Carbohydr Polym. 2013 Oct 15;98(1):1160-5. doi: 10.1016/j.carbpol.2013.06.069. Epub 2013 Jul 8.
High methoxy citrus pectin was oxidized by periodic acid to prepare a dialdehyde functionalized material. The effect of various reaction conditions, viz., reaction time, reaction temperature, pH of the medium, periodic acid concentration and solvent composition on the oxidation process was investigated. With an increase in the reaction time, the aldehyde content increased. However, the intrinsic viscosity of the system decreased indicating that degradation takes place simultaneously with oxidation. The amount of aldehyde generated also increased with an increase in reaction temperature and the concentration of periodic acid. Due to the polyanionic behaviour of pectin, greater aldehyde contents were obtained at lower pH. Keeping all other reaction conditions constant, greater aldehyde contents were obtained in water-ethanol system than in pure aqueous medium. Increase in the ethanol content increased the amount of aldehyde generated. FTIR spectra of oxidized pectin systems show a carbonyl peak at 1734 cm(-1). They further reveal that partial ionisation of-COOH groups takes place leading to a peak at 1614 cm(-1).
高甲氧基柑橘果胶被高碘酸氧化，制备二醛功能化材料。考察了各种反应条件，如反应时间、反应温度、介质 pH 值、高碘酸浓度和溶剂组成对氧化过程的影响。随着反应时间的增加，醛含量增加。然而，体系的特性粘度降低表明氧化过程中同时发生降解。醛的生成量也随着反应温度和高碘酸浓度的增加而增加。由于果胶的聚阴离子行为，在较低的 pH 值下获得了更高的醛含量。在保持其他反应条件不变的情况下，在水-乙醇体系中比在纯水溶液中获得了更高的醛含量。随着乙醇含量的增加，生成的醛量增加。氧化果胶体系的傅里叶变换红外光谱在 1734 cm(-1)处显示出羰基峰。它们进一步表明，-COOH 基团发生部分电离，导致在 1614 cm(-1)处出现峰。
